The invention concerns a foldable wheelchair.
The GB 15 61 694 describes a perambulator in which the child can be transported in both lying and seated position. The perambulator comprises a frame to which the wheels and the hand grips are attached, and a seat arrangement pivotally mounted on the frame and comprising a foldable seat covering. The tilt angle is adjusted manually and fixed by means of screws. The entire perambulator is foldable, whereby it is, however, not described how the components connecting the frame are designed to facilitate folding. This construction is not transferable to wheelchairs due to stability requirements. In addition, the seat frame must be placed in upright position or removed entirely before folding the perambulator.
The GB 20 29 33 40 describes a wheelchair comprising a motor drive and especially suited for severely disabled patients who can only move their fingers. The wheelchair is not foldable, so that no information on the details of the frame construction is given. The wheels and an upper frame with a seat which is tiltable around a horizontal axis are mounted on the lower frame. A mechanical, hydraulic or pneumatic adjustment mechanism is provided between the two frames for this purpose.
The GB 21 26 537 A describes a foldable wheelchair comprising two lateral frames to which the wheels are attached. Movable connection of the two frames is effected by means of two intersecting connection braces in the central area of the frame which can be moved scissor-like around a common folding axis in their intersection point. The tilt of the seat is not adjustable.
The joint axis of these transverse braces preferably extends in direction parallel with the seat and in longitudinal direction of the wheelchair.
The seat and backrest advantageously comprise a pair of seat panels also arranged foldably. The seat plates can form the whole or part of the seat or can act as the base for other seating elements, such as cushions and seat shells.
The pair of transverse pairs is preferably designed as a single piece and connected by a pressure hinge. The pressure hinge comprises at least one stop and at least one abutment, which abut on each other in unfolded state when the transverse braces lie in one plane. This defines the final position and prevents bending.
Since the seat plates are fastened on the upper side of the transverse braces, the transverse braces are also subject to pressure from above. In unfolded state the wheelchair is stabilised by the transverse braces and the seat plates, so that no additional arrest means are needed.
A further embodiment provides that the transverse braces possess at least one stop in the pivot area on the upper frame portion, which cooperates with at least one abutment of the upper frame portion when the wheelchair is in unfolded state. This also stabilises the unfolded state of the wheelchair. These stops and abutments can be provided alone or in combination with the pressure hinge.
According to a further embodiment, the juxtaposed brace pairs connecting the upper frame are replaced by individual elements. Tilt members are mounted preferably pivotally on the lower side of the seat plates on the upper frame portion.
These tilt members advantageously comprise at least one stop in the pivot area of the frame, whereby said stop cooperates with at least one abutment of the frame when the wheelchair is in unfolded state. occupant of the wheelchair is able to cause said tilt adjustment mechanism to operate to change the degree of tilt of the upper frame means relative to the lower frame means. The tilt adjustment mechanism can also be located backwards from said pivot means.